The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 05, 2016
Filed:
May. 02, 2013
Thyssenkrupp Industrial Solutions Ag, Essen, DE;
Christian Perbandt, Dortmund, DE;
THYSSENKRUPP INDUSTRIAL SOLUTIONS AG, Essen, DE;
Abstract
Disclosed is a method and system for reducing the nitrogen oxide off-gas concentration in a nitric acid plant operated under pressure and equipped with a residual gas purification first reactor configured to remove nitrogen oxides from the off-gas during steady-state operation of the plant, and a second reactor configured to remove nitrogen oxides from the off-gas during a start-up and/or shut down of the plant. The method includes, during start-up and/or shut-down of the nitric acid plant, passing pressurized nitrogen-oxide-containing off-gas from the nitric acid plant and a gaseous reducing agent for the nitrogen oxides into the second reactor charged with a catalyst, to reduce the NOx content in the off-gas by at least catalytic reduction. Using the process and system, a colorless start-up and shut-down of nitric acid plants is possible and the nitrogen oxide content in the off-gas during start-up and/or shutdown can be substantially lowered.